France's Bastille Day parade meets the Olympic torch relay in an ...

Paris is hosting an extra-special guest for France's national holiday Sunday — the Olympic flame lighting up the city's grandiose military parade for Bastille Day.

Just 12 days before the French capital hosts exceptionally ambitious and high-security Summer Games, the torch relay is joining up with thousands of soldiers, sailors, rescuers and medics marching in Paris beneath roaring fighter jets to mark Bastille Day.

While people around France mark the day with concerts, parties and fireworks, here's a look at what the holiday's about, and what's different this year:

What does Bastille Day celebrate?

On July 14, 1789, revolutionaries stormed the Bastille fortress and prison in Paris, heralding the start of the French Revolution and the end of the monarchy.

The holiday is central to the French calendar, with events across the country. It aims to embody the national motto of ''liberty, equality and fraternity,'' though not everyone in France feels the country lives up to that promise.

The Paris parade is the holiday's highlight. This year, it's paying tribute to those who freed France from Nazi occupation 80 years ago, with a re-enactment of the D-Day landings of June 6, 1944, and a display of emblems of the 31 countries whose troops contributed to the liberation. About half are African nations that were under French colonial rule during World War II.

Who takes part?

Some 4,000 people and 162 horses will march in the tightly choreographed show, among them units that served in NATO missions in eastern Europe, against Islamic extremists in the Sahel, protecting French territories in the South Pacific and global shipping corridors. They're joined this year by three German officers from a cross-border brigade.

The ornamental uniforms are rich in symbolism – most notably those of the French Foreign Legion sappers, with long beards, leather aprons and axes from their original role as route-clearers for advancing armies.

Overhead, 65 aircraft will fly in formations, including a British Typhoon fighter alongside French Mirages and Rafales, rescue helicopters and aircraft used in missions from Afghanistan to Mali or international drug busts.

President Emmanuel Macron and dozens of dignitaries will preside over it all.

These are scaled-back numbers compared to previous years, because of Olympics security measures. Around 130,000 police are deployed around France for the holiday weekend.

What's the political context?

This year's Bastille Day offers Macron a moment of distraction from political turmoil he unleashed with snap elections that weakened his pro-business centrist party and his presidency.

The result left a deadlocked parliament with no one clearly in charge. The prime minister could leave office within days, while the left-wing alliance that won the most seats is struggling to agree on a proposed replacement.

Meanwhile, Russia's war in Ukraine is threatening Europe's security. At a meeting with military leaders Saturday, Macron said France will keep up support for Ukraine and called for higher defense spending next year because of ''approaching threats.''

What's different this year?

The Olympic torch relay reaches Paris just in time.

The parade wraps up with the arrival of the flame, escorted by riders on horseback, 25 torchbearers, and cadets forming the shapes of the Olympic rings.

Usually, the parade travels from the Napoleon-era Arc de Triomphe to the Concorde plaza, where France's last king and queen were beheaded.

This year, Concorde has been transformed into a huge Olympic venue for breakdancing, skateboarding and BMX. So the parade route heads to the Bois de Boulogne park on the city's edge instead.

Olympic venue construction around the Eiffel Tower means spectators can't gather beneath the monument to watch its annual fireworks show, either.

After its Bastille Day appearance, the torch relay will swing by Notre Dame Cathedral, the historic Sorbonne university and the Louvre Museum before heading to other Paris landmarks Monday.